CPSC 100, Spring 1997:
Answers to Quiz #4

This is the fourth quiz from the course Computer Science 100: Principles of Computer Science, taught by David Eck. The answers that are included here are sample answers only. There might be many other answers to a given problem that would also receive full credit. See the home page for the text, The Most Complex Machine, for more information about the course.


Question 1: What were the contributions of Charles Babbage and Ada Lovelace to the history of computing?

Answer: In the 1830s, Charles Babbage designed a computing machine called the Analytical Engine. This machine was never built, but if it had been, it would have been the first general-purpose, programmable computer. Ada Augusta, Countess of Lovelace, was a friend and supporter of Babbage who wrote a book about his ideas. The book included some sample programs for the Analytical Engine, and as a result she is often considered to be the first programmer. Unfortunately, their work was almost forgotten for one hundred years and was only rediscovered after the first computers were built in the mid-1900s.


Question 2: What were the contributions of John Mauchly and J. Presper Eckert to the history of computing?

Answer: Eckert and Mauchly built the ENIAC, the first electronic, programmable computer. The ENIAC was begun during World War II to do military computations, but it wasn't actually finished until after the war. To be reprogrammed, the ENIAC had to be physically re-wired. However, even before the ENIAC was complete, Eckert and Mauchly had come up with the idea of a "stored-program" computer, in which the program would be stored as information in the computer's memory. In a stored-program computer, the programming can be changed easily, just by loading a new program into memory. Later, Eckert and Mauchly went on to found the first commercial computer company.


Question 3: What is a device driver, and why are device drivers essential to the functioning of a real computer system?

Answer: A device driver is the software that the CPU executes in order to communicate with and control another device, such as the keyboard, a sound card, a network interface card, etc. A device driver consists of subroutines and interrupt handlers specific to one particular type of device. Connecting a device physically to the computer is not enough to make it usable; the device driver must also be added to the system software.


Question 4: Explain the terms integrated circuit and microprocessor.

Answer: An integrated circuit consists of several (or perhaps, millions) transistors and other electronic components on a single small "chip" of silicon. An integrated circuit is faster and more reliable than the same circuit made out of individual transistors. A microprocessor is an integrated circuit that contains a complete CPU on a single chip. It was the development of microprocessors that made today's cheap personal microcomputers possible.


Question 5: When discussing the social impact of computers, one major area of concern is "privacy issues." Explain what this term refers to in the context of computers and computing.

Answer: Computers have made it possible to store and manipulate large amounts of data, which is stored in "computer databases." Tremendous amounts of data about individuals are collected by government, businesses and organizations and stored in this way. Although there are some legal controls over this data, much of it is available to anyone who wants to pay for it -- without any notification to the people whom the data is about. Many people are concerned that data about people can be stored and used without their permission, and even without their knowledge.


David Eck, 8 May 1997